A variety of methods are known for the polymerization of isomonoolefins. Polymerization methods also are known to polymerize conjugated dienes. However, copolymerization of isomonoolefin with a conjugated diene has presented many difficulties. The type of polymer involved, a copolymer of a monoolefin with a conjugated diene, presents many tantalizing possibilities always present in a large unexplored field of new compositions of matter, and compositions prepared by new methods. The search for methods to prepare such copolymers continues.